1. Technical Field
The present invention relates to an image display device.
2. Related Art
A head mounted display (HMD), which is a display device mounted on the head, is known. For example, the head mounted display generates image light, which represents an image, using a liquid crystal display and a light source and guides the generated image light to the eyes of a user using a projection optical system, a light guide plate, and the like to thereby cause the user to visually recognize a virtual image. The head mounted display is connected to an external device such as a smart phone by a wired interface such as a Micro USB (Universal Serial BUS). The head mounted display can receive a video signal from the external device in conformity to a standard such as MHL (Mobile High definition Link). Similarly, the head mounted display is connected to an external device by a wireless interface such as a wireless LAN. The head mounted display can receive a video signal from the external device in conformity with a standard such as Miracast. The head mounted display can cause, on the basis of the video signal received in this way, the user of the head mounted display to visually recognize a virtual image same as an image displayed on a display screen of the external device.
Japanese Patent No. 3968467 (Patent Literature 1) describes an AV (Audio Visual) system that can integrate and display the present program video, information concerning the present program video, and program information of other channels on one screen. Japanese Patent No. 5082722 (Patent Literature 2) describes an image display device in which virtual screens are provided adjacent to display screens of a plurality of computer devices and users of the computer devices can operate windows on the virtual screens.
In the technique described in Patent Literature 1, an analog broadcast receiving unit and a digital broadcast receiving unit are exemplified as AV devices connected to the AV system. That is, the technique described in Patent Literature 1 targets videos transmitted and received between specific devices and has low versatility. The technique described in Patent Literature 2 merely provides display means different from the display screens of the computer devices, that is, the virtual screens and cannot integrate the display screens of the plurality of computer devices.
Therefore, there has been a demand for an image display device that can integrate displays in external devices around the image display device (peripheral devices). Besides, there have been various demands for image display devices such as improvement of versatility, improvement of usability, improvement of convenience, improvement of reliability, and a reduction in manufacturing costs.